1. Technical Field
The present invention relates generally to the field of analogue gauge and accessory encasements, and more particularly, to instruments for mobile deployment in harsh outdoor marine, recreational, and horticultural locations as well as static industrial, domestic, and commercial usage sectors.
2. Related Art
Many gauge instruments such as clocks, weather instruments, speed logs, inclinometers and like used in, for example, the mobile sectors described above, are typically mounted to a wall, bulkhead or other appropriate surface in a variety of methods all of which have some disadvantages. For example, when instruments are deployed into moving platforms such as ships, yachts, power boats, mobile homes and the like, it is essential they be mounted securely and not left to swing on the single suspension point normally provided for in devices intended only for static deployment as the movement of the vehicle may cause the instrument to easily dislodge or fall and be damaged and/or be rendered inoperable.
The traditional analogue method of displaying a measured variable traces back in antiquity to the circular procession of the Northern Hemisphere invention of the Sun Dial. Thus, instrument casings historically have followed a particular design geometry of a circular drum type encasement housing a mechanism with a central indicating ‘clockwise’ procession of a hand or pointer directly derived from the shadow precession cast by the gnomon of the Sun Dial. Such drum type encasements have usually been arranged to have a rear flange having three or four equally spaced holes to enable screw mount from the front of the device. The simple drum and flange shape for clocks, chronometers, barometers and the like has been echoed by the style of pressure and temperature gauges and the like that became the norm from the early days of steam and the Industrial Revolution. With the advent of digital displays, the circular analogue drum and flange has been applied to an ever expanding plethora of gauge devices. Thus was established a whole traditional genre for fixed instrument design that has acquired something of a proscribed norm. But the rear flange has not been without its disadvantages particularly in their current evolution.
Instruments need to be removed for service such as battery change and resetting procedures. When flange screw mounted to a wall or bulkhead, removal requires the use of tools and any mishap such as a screwdriver escaping from the control of the screw slot will damage the surrounding case and wall areas. In addition, repeated removal and replacement results in screw holes gradually enlarging, thus rendering the mounting weak and eventually requiring a new position to be selected, which results in surface disfigurement. These situations become aggravated if there is a multiplicity of instruments mounted in similar fashion.
More sophisticated systems, such as the hinge bezel system, have been developed to overcome some of the flange screw disadvantages. In these system, a bezel provides an integrally cast hinge and closed locking screw latch device that hinges away from a wall mounted drum case with a back flange, to expose the instrument rear for service and reset functions. However, these systems are expensive to manufacture.
Often, traditional instrument encasing systems with a non-hinged but screw fitted bezel, have fully enclosed back plates permanently fixed to the case rear flange. These systems generally fail to provide adequate ventilation of the instrument casing and also make it difficult to access to the instrument housed therein.
It also is difficult to mark out a location for fixation of encasement system. Typically, the process usually involves placing and holding the cased instrument in the desired ultimate position and marking through the holes in the case flange. This can be an arduous and inaccurate process if not performed correctly and risks resulting in a misaligned attachment quite simply because one cannot simultaneously be close to support the device in situ and at a distance to visually align the device.
Traditional instrument encasing systems, especially those used in the harsh marine environment, usually are made of brass for a variety of reasons: brass is extremely tolerant of salt water laden air; brass does not corrode in the same way as steel, but has similar or adequate strength for most purposes; brass oxidizes—or ‘tarnishes’—to a thin black brown film if left untreated, but does not rust away like mild steel; and the yellow color of brass retains a pleasing and highly acceptable aesthetic. In addition, brass does not spark if struck and is non-magnetic and thus does not distort instrument indications such as compasses and escapement chronometers. Therefore, cases and devices such as sextants, telescopes, dividers and the like that may be in proximity to compasses and chronometers also were traditionally made of brass or housed in brass for appearance, conformity, resistance to salt water laden air, durability and/or anti-magnetic property. However, it is difficult to maintain the appearance of brass's finish unless it is lacquered to inhibit tarnishing oxidation. Brass also has become an extremely costly, commoditized raw material due to the high demands for its copper constituent in the energy generation and transmission sectors and all manner of inductive electric actuators, printed circuits and wire conductors.
In the early 20th century, stainless steel became a universally recognized reality. However, this alloy has been slow to gain wide usage in harsh marine environments, typically in boat and ship building, where galvanic action can lead to corrosion of even ‘stainless’ steel. Thus the higher cost of stainless to normal steels becomes unjustifiable. Moreover stainless steel does not readily lend itself to traditional steel shipbuilding techniques where certain established art and skills can partially destroy some the attributes of the stainless alloy.
Protective coatings such as traditionally shellac, or more typically synthetic and epoxy lacquers, help to maintain brass and prevent tarnishing, but they are problematic and susceptible to chipping and scratching that locally exposes the protected brass to the atmosphere resulting in localized oxidation. Once surface penetration occurs, further degradation is inevitable and unpreventable as moisture penetrates the lacquer to brass interface, causing even more chipping and peeling, and consequently further oxidation.
Accordingly, a need has long existed for improved instrument encasing systems.